The invention finds application particularly in the field of the truck and transport technology, where the vehicle is a truck and the unit is a transported unit. Within the framework of the invention, under transported unit there is meant a unit that is connected with a self-propelled towing device (tractor or towing machine) of a truck and/or is transportable by such a towing device. The unit may be a construction which travels on its own wheels, such as a semitrailer or trailer coupled in a known manner with the towing device. The transported unit, however, may also be a container or transporting crate which has a given external geometrical configuration and which is situated in a certain position on a loading platform of the towing device.
German Offenlegungsschrift (Laid-Open Application) DE 26 16 948 A1 describes a two-part vehicle spoiler whose adjustable part close to the road is pivoted away from the road at low speeds and which, forced by the travel-generated air stream, pivots back as a function of increasing vehicle speed.
German Offenlegungsschrift (Laid-Open Application) DE 38 28 752 A1 describes a further development of a device for adjusting a vehicle spoiler. The device, based on a continuous evaluation of detected operational parameters of the vehicle (such as speed, acceleration and travel in curves), adjusts the spoiler such that an optimal road-handling ability of the vehicle is ensured.
German Offenlegungsschrift (Laid-Open Application) DE 38 23 161 A1 discloses a wind deflecting device situated between the driver's cab and the adjoining semitrailer. For obtaining, in a simple manner, a uniform appearance with identical flow conditions between the cabs and/or the semitrailers of substantially different geometrical configurations, a kit, which comprises aerodynamic and complementally shaped unitary wind deflecting flaps or plates adjustable from the cab as well as different intermediate elements, is provided at the assembly plant. During vehicle assembly at the plant, a selection is made from the kit in accordance with the geometrical variants at hand.
An apparatus generic to the invention is disclosed in European Patent Application EP 1 031 497 A2 which relates to a mechanism for adjusting an airflow deflector mounted on the roof of a vehicle cab, for example, on the roof of a towing machine or tractor of a truck. In order to be able to adapt the position of the airflow deflector to trailers with different geometrical design in a possibly economical manner, the described apparatus includes an electrical setting device which comprises a spindle, a spindle nut and a rod connecting the spindle nut with the airflow deflector. The rotation of the spindle may be controlled from the cab of the towing machine to enable the driver to manually vary the position of the airflow deflector. The actual position of the airflow deflector may be displayed in the cab.
The operation of the above-outlined, relatively flexible and convenient apparatus which is adaptable to trailers and semitrailers of different geometrical configurations, largely depends on the experience and skill of the driver or relevant personnel for setting the airflow deflector in its flow-optimized position. Should the operator miss an (optimal) adjustment of the position of the airflow deflector, such a circumstance affects directly the aerodynamics of the entire system (for example, the Cw value) and thus has, among others, an adverse effect on the fuel consumption and travel noise behavior of the vehicle. To avoid such misses, an intensified instructional and supervisory outlay is required which, however, particularly for the costs involved, is to be avoided to the extent possible.
It is thus an object of the invention to further develop an apparatus of the earlier-described type such that, even when using different transporting units having different external geometrical configurations, an optimal position of the airflow deflector is ensured at all times.